A study published in Psychology,Public Policy, and Law examined patterns and correlates of arrest/re-arrests among offenders with a serious mental illness over a 4-year period. County criminal justice records and health and social service datasets were used to identify and describe inmates jailed in Pinellas County, Florida , between 7/03 and 6/04. A total of 3,769 participants (10.1% of arrestees) had a serious mental illness. Participants averaged 4.6 arrests (SD = 3.9, median = 4) and 150.6 days in jail (SD = 175.0, median = 90).Working from the trajectories of offending theory and literature, the study authors used latent class growth analysis to identify three classes of offenders with consistent numbers of arrests over a 4-year period and nearly parallel arrest trajectories; a sporadic arrest class (n = 469) with minimal arrests, a low arrest chronic class (n = 3,090, about one arrest/year); and a high arrest chronic class (n = 210, about four arrests/year). Analysis of arrests by age group within each of the classes suggested that for the low and high arrest chronic classes arrest rates persist throughout adult life. Statistical analysis showed that homelessness, a co-occurring substance abuse diagnosis, fewer mental health outpatient service contacts and more mental health emergency room/inpatient contacts were associated with being in a class with more arrests. Arrests among offenders with a serious mental illness appear to be unusually high, to be firmly established in late adolescence and to persist over time. Successful strategies to reduce the arrest rates of this population must address the needs of these offenders early in their criminal careers.